Pacifiers and Speech Disorders: Preschoolers with speech disorders were three times as likely as other children to have used a pacifier for at least three years, according to an observational study in BMC Pediatrics. Out of 128 Chilean 3- to 5-year-olds in the study, 61 scored below normal on a standardized speech test. In addition to the pacifier trend, children in this group were also thrice as likely to have started bottle-feeding before nine months of age. Previous studies have shown that certain sucking behaviors in early childhood are associated with oral and dental deformities, but evidence of these behaviors' effect on speech has been inconsistent, the researchers said.
Caveat: The infants' sucking behaviors were based on parental recollections rather than direct observation. A larger, randomized trial is needed to validate the findings, the researchers cautioned. (Read the report.)
Nicotine and Cancer: Nicotine patches appear to promote the spread and re-growth of cancer tumors, according to a study in PLoS ONE. Previous studies have found that nicotine increases cell proliferation and tumor growth independently of the carcinogens in tobacco smoke, but this was the first study to show that nicotine patches increase the risk for tumor recurrence and metastasis. In one of several experiments, the scientists implanted two groups of mice with cancerous tumors. They injected one group with nicotine three times per week—reaching average bloodstream levels roughly similar to those of a human heavy smoker. The other group received dummy injections of an inactive substance. After 18 days, the tumors in the nicotine group were more than three times as large as those in the control group. Over-the-counter nicotine patches had a similar, though smaller effect. The researchers also found that surgically removed tumors grew back in 59% of the nicotine-treated mice but in only 19% of control mice, and nicotine increased nine-fold the rate that tumors implanted in the mice's backs spread to their lungs.
Caveat: Mouse and human cancers can differ significantly. This study did not examine how nicotine affects human tumor growth. (Read the report.)
Fertility Treatment: Women who lie down for 15 minutes after receiving artificial insemination appear to have a 50% higher chance of becoming pregnant, according to a study in BMJ. Intrauterine insemination—in which a doctor injects sperm directly into the uterus—is likely the most common type of fertility treatment in the world, but this was the first large study to examine how keeping patients briefly immobile affected the procedure's success rate. The researchers randomly assigned 391 couples to the experimental group or to the control group, in which the women were allowed to move around immediately after insemination. After up to three treatment cycles, 27% of the women in the experimental group became pregnant, compared with 18% of the women who were allowed to move around. The reasons for the differences were unclear, but the researchers suggested that the change in gravity from standing up could have caused the sperm to leak away from the uterus or slow down in the fallopian tubes.
Caveat: The overall rate of pregnancy in this study was significantly lower than at many fertility centers, according to an editorial that accompanied the published paper. (Read the report.)
Heart Disease and Hip Fractures: Genetic factors appear to explain much of the connection between heart disease and hip fractures, according to a study of nearly 32,000 Swedish twins in JAMA. Participants in the study who were diagnosed with heart failure were five times as likely as other subjects to later fracture a hip. But, remarkably, the identical twins of these patients also became more likely to later fracture a hip—their risk was nearly four times as great as other subjects', even though they hadn't been diagnosed with heart disease. The researchers observed a similar, though less robust effect for identical twins of stroke victims. Cardiovascular disease and bone weakness share some biological pathways.
Caveat: Though the study enrolled many subjects, there were fewer than 400 cases in which an identical twin fractured a hip after his or her sibling was diagnosed with heart disease. For this reason, the risk estimates varied widely. (Read the report.)
Recovering from Tonsillectomy: A three-day course of antibiotics was no less effective than the standard seven-day course for helping children recover from tonsillectomy, according to a study in the Archives of Otolaryngology–Head & Neck Surgery. The researchers randomized 49 patients into two groups: one that received a seven-day course of amoxicillin, and another that received a three-day course of that antibiotic followed by four days of placebo. Patients on the three-day course returned to a normal diet after an average of 5.7 days, while patients on the seven-day course took 6.0 days on average—a statistically insignificant difference. The groups did not differ on the number of days it took to return to normal activity or the amount of pain-relief medication used.
Caveat: Enrolling more patients could have revealed significant differences that this small study missed. Pain in this study was not measured directly, but rather by the use of pain relievers. (Read the report.)